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I hate issueing inverted devices and are always quite nervous about patient's tolerance to such correction.

I read some studies which say we should start patients at 25 degrees (even if they require more) initially just for 'wearing in'. Do people follow this guideline usually or just go with the correction you feel necessary?

My patient is currently in Prothotics and just not providing enough correction. With some forefoot additions and enough rearfoot correction I think that an inverted device will help. She also has tight gastrocs which I am issueing heel lifts on the device to assist with this.

My patient is currently in Prothotics and just not providing enough correction.

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You answered your own question:

She also has tight gastrocs

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Theoretically, this will make anyone pronate "through" the orthotic. Deal with this first - manipulate the fibula; get them stretching; use heel lifts.

BTW - did you know that some people actually pronate more on inverted orthotics and they still get better? :dizzy:

BTW:

Prothotics

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For anyone outside Australia reading this, these are the very inverted in the heel prefabs that are trademarked as Prothotics in Australia and not the Atlantic Footcare brand of Prothotics used in the rest of the world that are neutral under the heel

I gave her a strict stretching regime but compliance has been difficult..she feels as though she has been suffering with the Plantar Fasciitis for 7 or so years and is wanting to have surgery (which I am obviously trying to steer her clear from). I though an Inverted with a Kirby skive and heel posts would be a good start

You are not really supposed to skive a device made in Richard Blake's way, if you get a Blake inverted device at 25 to 30 degrees it will depend on who makes it as to how inverting it really is. There is a local large factory that makes very washed out Blakes and at 25 deg it will still only be moderate. If a Blake is made the way he intended it then you won't need the skive.
regards Phill Carter

You are not really supposed to skive a device made in Richard Blake's way, if you get a Blake inverted device at 25 to 30 degrees it will depend on who makes it as to how inverting it really is. There is a local large factory that makes very washed out Blakes and at 25 deg it will still only be moderate. If a Blake is made the way he intended it then you won't need the skive.
regards Phill Carter

Ok Kevin, but the original writings that I used to recreate his methods never talked about skives....and if you use his original recipe without lots of infill you get one mother of a device when you do a 35 deg, can't imagine why you would need this with a skive as well.....and how much lateral instability it would cause....??How ever my real point was that in Aus who ever actually makes it is going to greatly effect what you actually get when you order one.
regards Phill Carter

Firstly I think you need to rewind a few steps. You seem to have become quite focussed on adding more "correction". Perhaps it would help if you thought more in terms of getting away from the pathology.

Firstly, ref the ankle equinus, if the patient cannot place their foot in your "corrected" position with the ankle joint in its required range then no amount of medial posting or inversion will make it do so. Creating a shape on the top of an orthotic does not mean the foot will adopt that shape. Remember orthotics push, they don't hold.

If the leg cannot travel over the foot because of the equinus it will compensate by pronating to get a few more degrees dorsiflexion. If your orthotic prevented that happening (it won't) then it would have to compensate somewhere else, perhaps by abducting more or by early heel lift. These can cause other problems.

Now consider the plantar fascia and what plane it is functioning in. You are trying to reduce tissue stress in a structure which lies mainly in the sagital plane by inverting the foot in the frontal plane. For this to work you must understand how the triplanar sub talar joint will acheive this. What is the planal dominance? Is the inversion not working because its a big ole frontal planal dominance and the nav is drifting over the top of the orthotic?

Also consider where exactly the pain is coming from. If its been 7 years there is probably a good deal of generalised inflamation. Have her walk up and down the corridor a few times and notice whether it hurts on heel IMPACT or on heel LIFT. If its on impact (when the PF is not especially tensioned) then something cushioned or a steroid injection might be as helpful as adding more medial wedging.

I appreciate the desire to keep her out of surgery (beleive me I do ), but it sounds to me like the ankle Equinus is the real issue here. Inverting the foot is all very well but to put it crudely, you don't treat a boil on your bum by lancing your elbow.

Regards
Robert

Robert Isaacs
Specialist in Biomechanical Therapies

Semper in excretum sum sed alta variat

Never be a spectator of unfairness or stupidity. Seek out argument and disputation for their own sake; the grave will supply plenty of time for silence. Suspect your own motives, and all excuses.
Christopher Hitchens

Ok Kevin, but the original writings that I used to recreate his methods never talked about skives....and if you use his original recipe without lots of infill you get one mother of a device when you do a 35 deg, can't imagine why you would need this with a skive as well.....and how much lateral instability it would cause....??How ever my real point was that in Aus who ever actually makes it is going to greatly effect what you actually get when you order one.
regards Phill Carter

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The reason that his original writings didn't include a medial heel skive was because I was one of Dr. Rich Blake's students and helped Rich make his inverted orthoses back in 1981-1983 when I was a podiatry student. This unique experience ultimately led me to the creation of the medial heel skive technique in 1990 as an easier way to create an inverted heel cup in a standard functional foot orthosis. In all honesty, wthout Rich Blake's influence on my education and knowledge, it is unlikely that I would have had the foresight to create the medial heel skive in 1990.

Concluded that even tho kinematic RoM was not changed the kinetics in terms of internal moments were and this would probably result in reduced stess and injury to tissues. NB There may be increased risk of trauma where the moments are increased.

With Blake orthoses, there is a point if diminishing return. The more you invert the cast, the more you need to fill the arch. We routinely make 25, 35, and 45 degree Blake type inverted orthoses. But you can accomplish much of the same effect with a 10 to 20 degree inverted cast and a medial (Kirby) heel skive. The advantage is that the corrects tend to be less subjective because you need less fill. Less filling, isn't that a beer commercial?
Respectfully,
Jeffwww.root-lab.com

I suspect you and I are actually saying the same thing Jeff...a big Blake has lost most of it's touch with the reality of the foot by the time you drape that foot back down over the Mont Blanc Massif......and if you fill it in heaps you end up with a fairly flat device, which is not what you started out wanting.
regards Phill Carter

I have to admit that I have never used a Blake inverted device and despite years ago reading about the technique of making them I can't see the difference between this technique and just adding a massive medial wedge to an orthosis. I realise that there might need to be a lateral flange and deep heel cup and the arch might need flattening to stop it digging in but can someone explain the subtleties of the construction and use of the inverted technique.

I do have a lady coming in who has deep knee pain ("feels like its deep inside then radiates up my leg") that comes on only when weight bearing and the pain radiates up the ITB but cannot be elicited by palpation or any clinical test. EG pressure on the joint line causes no pain, no pain along ITB, no pain sub pattella and not crunchy, no pain at pes anserinus, no pain forced extension, no pain full flexion, no pain internal external torsion, no drawing pain.

She has extremely pronated STJ's and internally rotated tibia - squinting patella - and genu valgum with tight knee abductors loads of slack in the frontal plane knee RoM. The GP diagnosed wear in the minisci. Anyway I thought reducing the frontal and transverse plane moments about the knee may reduce joint forces and change the weight bering orientation of those forces. Therefore a Blake inverted with Medial skive might be the answer here. She did come in in 2006 with the exact same symptoms but did not want to pay for bespoke orthoses so I fitted medial full length 5dg wedges to here Scholl insoles. The knee pain went away and she stopped using the wedges but had forgotten about that till I reminded her today. Later notes show she had vague reasons why she stopped using the wedged insoles, mainly about what she was used to and shoe fitting in summer shoes.

Cheers Dave

Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.

If you look at a positive plaster model of a foot and put a nail in the 5th MPJ and then a nail in the 1st mpj, from the plantar side of course, as though you are making a pair of orthoses what happens as the nail in the 1st gets longer and longer? This is all you are really doing to the foot with the Blake method, that nail gets longer and longer until the calc is inverted 25, 35 or more deg. If you actually look under the plaster foot as this occurs what you are doing is elevating the medial side of the foot further and further from the floor. The "control area" is obviously in the region of the sustentac and plantar calc and hindfoot, these get further off the floor to a potentially ridiculous level that has no chance of fitting in a shoe. Your challenge, should you choose to accept it is to "drape the forefoot back down to the floor in a way that is tolerable but does not remove all the inversion that you have created with that long nail. The difference here(to your big wedge) is the midfoot twist at the lis franc that the Blake creates by raising medial rear structures and allowing the met heads to become plantigrade over the device.
Read Blakes stuff, it's dated now, but was good new ideas at the time, and the technique can lead to a good orthosis when done well, but it is a challenge to get right. As a shape they will tend to create more change at the knee(than a mod Root), focus plantar pressure under 4 and 5 met shafts and heads, foster a lateral low gear toe off, be a nightmare for women in shoes, and even a little awkward in some mens shoes. There are always other opinions and my observations are by no means exhaustive or applicable in every case. But I have used them myself and made quite a few of them myself.
regards Phill Carter

Yes good reply thanks, I had an idea that the forefoot was allowed to plantarflex. So I guess the clinician must evaluate whether or not the foot is suitable for this type of orthosis. I.E> if the midtarsal joints / met cuneiform joints are very stiff then this might not be a good orthosis to use. Years ago I did have a paper describing how to make these devices but it seems to have disappeared into the memory void of one of my computers. Prof Kevin K kindly found me a copy of Blakes original paper and it does say the anterior platform corrects the forefoot back to 0dgs. I guess the amount that you let the forefoot plantarflex / pronate / evert is part of the prescription parameters. Would this also allow a certain amount of forefoot abduction?

Cheers Dave

Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.

As I stated in an earlier posting, Rich Blake was my Biomechanics Fellow when I was a 2nd year podiatry student at CCPM. Myself, and a number of my running buddies in my class (we had 5 guys in our class that had run the Boston Marathon in the years prior to entering podiatry school) hung around with Rich as much as possible to learn from him about sports medicine and orthoses during our student years. We all helped Rich make his BIOs when he first started doing them in about 1980-1981. I probably made 20-30 pair of BIOs before I finished podiatry school in 1983, directly under Dr. Blake's supervision.

The medial arch fill of the BIO is probably the most subjective part of the plaster technique. Rich would always have us note the shape of the medial longitudinal arch contour that was present in the non-corrected positive cast and then try and put that same medial longitudinal arch contour into the BIO. The other problem with the BIO was that when it is inverted more than 15 degrees, (we did them up to 45 degrees) we had to add extra plaster medially on the positive cast to prevent the orthosis from being too narrow, since inverting the cast will narrow the width of the plantar aspect of the foot. In addition, Rich had us putting in plaster plantar fascial accommodations into all the BIOs which required quite a bit of extra work. Basically, making a standard BIO build on a positive cast took twice as long as making a standard Root functional orthosis plaster build on the positive cast.

Because of the difficulty in making BIOs consistently and the inordinate amount of time required to make the BIOs, I began experimenting with the medial heel skive modification in 1990 at Precision Intricast lab with the owner of the lab, Paul Rasmussen, when the lab was still in Lodi, only 25 minutes from my office. Most ortosis labs now prefer the medial heel skive modification for putting an inverted heel into the positive cast, versus the BIO, since the BIO takes so much extra time to build and is much harder to get the medial arch contour consistent than does putting in only a medial heel skive which does not affect the medial arch contour of the positive cast.

I have been thinking that I shoud give Rich Blake a call and see if I can have him do a posting on Podiatry Arena about his technique. Like I said earlier, seeing Rich's pioneering work in "breaking away" from the standard Root orthosis techniques (and harassment he got from most of the Biomechanics Professors at CCPM in doing so) was extremely helpful to me while I was a podiatry student at CCPM, greatly helped broaden my perspective of available orthosis techniques and, I believe, was instrumental in my eventual development of the medial heel skive technique in 1990.

Hi Guys,
I have had the same issues with the technique and have pursued other options, locally there is the so called DC Wedge developed by one of the labs, which about 10 years ago I reverse engineered and gave my own tweek to, so now I tend to use that addition to the lateral plantar heel rather than removal of the medial plantar heel. This method gives you separate control of medial arch shape and height, lateral cuboid shape and height and degrees of angular heel/calc inversion. This is of course available to you with any other orthoses plaster method, but as has been said some methods require more time, materials and skill, all of which it is better to minimise in lab situations.
regards Phill Carter

Hi Guys,
I have had the same issues with the technique and have pursued other options, locally there is the so called DC Wedge developed by one of the labs, which about 10 years ago I reverse engineered and gave my own tweek to, so now I tend to use that addition to the lateral plantar heel rather than removal of the medial plantar heel. This method gives you separate control of medial arch shape and height, lateral cuboid shape and height and degrees of angular heel/calc inversion. This is of course available to you with any other orthoses plaster method, but as has been said some methods require more time, materials and skill, all of which it is better to minimise in lab situations.
regards Phill Carter

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I described a plantar lateral expansion to create an inverted wedge effect in the heel cup of an orthosis either here or on the JISC mail podiatry list some years back. I agree that shaving the medial side can reduce the arch height of the device when doing a medial heel skive.

The optimum medial arch height is the part of the orthosis that I am least sure about. One reason that I'm not sure about what to do here is that I think different people with the same arch shape will prefer different arch heights to their orthotics. I've seen some people who I've given devices to with what I felt were fairly high arches who have craved more. In my own feet, arches that were too high caused severe pain. One variable that might be worth looking into is the change in arch height non weightbearing versus hight weigthbearing. I'll be there is more.

The Blake inverted started me thinking about arch height. It is certainly possible to make the arch of the device so high that the first metatarsal can't reach the ground when the patient is standing on it.

The variability in preferred arch height across people is one reason I have a problem with the MASS technique for casting. I'm quite sure that it is not the right technique for everyone, but some people really like the devices made from it.

Dave and Phil:
I have been thinking that I shoud give Rich Blake a call and see if I can have him do a posting on Podiatry Arena about his technique. Like I said earlier, seeing Rich's pioneering work in "breaking away" from the standard Root orthosis techniques (and harassment he got from most of the Biomechanics Professors at CCPM in doing so) was extremely helpful to me while I was a podiatry student at CCPM, greatly helped broaden my perspective of available orthosis techniques and, I believe, was instrumental in my eventual development of the medial heel skive technique in 1990.

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We (Root Lab) were doing lab work for Rich Blake back in those days (still do some) and we helped him refine the Blake Inverted Orthotic technique. My father actually told Rich to name the device the Blake Functional Orthosis because it was significantly different from a Root type Functional Orthosis and he felt Rich should get credit for it. Originally Rich added all the inversion correction extrinsically to the positive cast. We developed a technique of pouring the negative cast inverted rather than adding an inverted balance platform to a cast that was poured vertical because it was more efficient. In theory, the end result is the same but in reality there tend to be subtle differences in the shape of the shell when using these two, different techniques.

One difference of note between a medial skive and inverting a positive or negative cast has to do with the axis of the heel skive as compared to the axis of inversion of the positive or negative cast as a unit. The medial heel skive tends to parallel the sagittal plane and removes a wedge in the frontal plane. When you highly invert a positive or negative cast, the axis of rotation is more abducted. In other words, the 5th met head and heel contact the supporting surface. The more you invert the cast, the more lateral the contact point in the heel becomes. If you look at a Blake type orthosis, it is more of a tri-plane correction than a medial heel skive. If you abducted your medial heel skive, it would better resemble the heel cup of the Blake inverted device (for better or worse?).

One thing that Rich Blake did, was popularize the use of significantly deeper heel cups in orthoses. Prior to Rich, most podiatrists were not using deep cups. Labs had to lean how to press deeper heel cups because of Rich Blake’s influence. As a rule, Blake inverted orthoses tend to be wider, and more bulky than orthoses with medial heel skives. They also tend to require more practitioner modification for optimum tolerance and fit. They make excellent device for pediatric flatfoot although it was originally developed as a running orthosis to address the varus angle of the limb.

I hate issueing inverted devices and are always quite nervous about patient's tolerance to such correction.

I read some studies which say we should start patients at 25 degrees (even if they require more) initially just for 'wearing in'. Do people follow this guideline usually or just go with the correction you feel necessary?

My patient is currently in Prothotics and just not providing enough correction. With some forefoot additions and enough rearfoot correction I think that an inverted device will help. She also has tight gastrocs which I am issueing heel lifts on the device to assist with this.

Click to expand...

I use supination resistance, available stj rom along with the insight of what am I trying to achieve (triplanar control) prior to prescribing an inverted device. Remember the need for contralateral control (ie lateral column) when inverting the calcaneous. If you do this the a 5:1 cast angle to correction will be ok.